Yes, Donald Trump walked away with the most delegates after the Super Tuesday Republican primaries on March 1, but a closer look at the numbers shows just how vulnerable he is. Is he the front-runner? Absolutely. Is he invincible? Absolutely not. To understand why, it’s important to analyze the delegate tally so far and the primary calendar going forward.

Heading into Super Tuesday, Trump appeared to be in a commanding position. He had won 3 of the 4 contests so far, swept the delegates in South Carolina, and had won 65 percent of all delegates awarded. Not only that, polls showed that he was primed to crush Florida Sen. Marco Rubio and Texas Sen. Ted Cruz in the Super Tuesday SEC primary.

But that’s not what happened. Trump won a majority of the states up for grabs — 7 of 11 — but the delegate total tells a different story. Cruz crushed him in Texas (Cruz won every single congressional district and the statewide popular vote) and also ended the evening with unexpected wins in Oklahoma and Alaska. Rubio notched his first win in Minnesota and nearly eked out a surprise victory in Virginia. Kasich nearly toppled Trump in Vermont, losing by only 1,400 votes.

Although the numbers are not yet set in stone, it appears certain that Trump failed to win a majority of delegates on Tuesday night. The bombastic New York real estate tycoon will likely end up with roughly 42 percent of the available delegates (around 250 delegates), while Rubio and Cruz combined won with 53 percent (roughly 320 delegates), a clear majority of the 595 Super Tuesday delegates at stake.

You read that correctly: Cruz and Rubio, not Trump, walked away with a majority of Super Tuesday delegates.

That is a big deal. It’s a big deal because Super Tuesday erased Trump’s delegate majority. He headed into the evening with 65 percent of the delegates awarded thus far and walked out with 47 percent. It’s a big deal because it shows that the barrage of attacks on Trump from Rubio and Cruz did some significant damage despite the fact that the attacks were only launched a few days ago.

Also concerning for Trump is that he’s now a dismal 1-3 in the closed primary states of Iowa (Cruz), Alaska (Cruz), Oklahoma (Cruz), and Nevada (Trump). In contests where only Republicans are allowed to vote on who should be the Republican nominee for president, Trump has performed quite poorly. In the ten states where elections will be held between now and March 15, eight of them are closed and allow only Republicans to participate. Of the 21 contests between now and the end of March, only 8 allow non-Republicans to participate.

So what is the path forward for the non-Trump candidates? Do they have a chance? They do have a path, but it is a narrow one.

First, they must continue to rack up delegates in the ten proportional contests that will be held on March 5 (KS, KY, LA, ME), March 6 (Puerto Rico), March 8 (HI, ID, MI, MS), and March 12 (DC). In those ten races, 347 delegates will be at stake. Cruz and Rubio need to focus on denying Trump delegate majorities in those states and perhaps picking off an outright win here and there. Because all of these states allocate their delegates proportionally (as opposed to winner-take-all, where the winner gets everything regardless of whether he or she wins a majority of the actual votes), demands that this or that major candidate drop out will likely fall on deaf ears.

The next big milestone in the Republican primary is March 15. That’s when the first winner-take-all states appear on the calendar. Five states (FL, IL, MO, NC, OH) and 358 delegates will be in play on March 15 (although March 15 will garner most of the media attention, the March 5-12 contests provide almost the same amount of delegates). Florida and Ohio are true winner-take-all states, while Illinois and Missouri are winner-take-most states. North Carolina proportionally allocates its delegates. So what’s the anti-Trump play here?

Rubio must win Florida. That’s it. That should be the focus of his entire strategy. Nuke Trump from orbit and salt the ground where he once stood. If Rubio can prevent Trump from winning Florida’s 99 delegates, conservatives may well be able to deny Trump the 1,237 delegates he needs to win the nomination on the first ballot at the Republican convention. If Rubio loses Florida, he’s done. His partisans will certainly assert otherwise, but if he is unable to secure victory in his home state, it’s over. And if Rubio believes heading into March 15 that he will lose Florida, then he should very seriously consider dropping out and throwing his support behind Cruz.

Cruz’s March 15 strategy is also fairly simple: overperform. As of today, he’ll trail Trump by only 100 delegates or so. He’s closer to catching Trump than Rubio is to catching Cruz. He will likely focus on surprises in Missouri and North Carolina under the assumption that Trump will focus his attention on Florida and Illinois. If he’s feeling particularly bold, he might even make a play for Illinois.

Kasich’s strategy is every bit as simple as Rubio’s: win Ohio. If he can’t win Ohio and deprive Trump of its 66 delegates, he has absolutely no business staying in the race. Unless he’s angling for a VP spot, that is (which he probably is, because he has no path to the presidential nomination). Cruz and Rubio are in no real position to be offering that to anyone right now, which makes Kasich a prime takeover target for Donald Trump. He bought Christie out, so why not Kasich? If Kasich decides that he can’t win Ohio, don’t be surprised if he bails before election day and endorses Trump.

Trump’s strategy is also rather easy to discern: he needs to start winning a majority of delegates in each state. That means a clean sweep on March 15. Four of those fives states have open primaries, so the odds are clearly in Trump’s favor. If he can amass a majority of delegates between March 5 and March 12 and run the table on the four winner-take-all states on March 15, the race is over. He knows a win in Florida sinks Rubio, so he will certainly spend a lot of time and money there in attempt to bounce Rubio for good. Illinois, a delegate-heavy winner-take-all state which allows Democrats and independents to vote in the Republican primary, is also ripe for a Trump win. Expect to him to focus primarily on those two states.

The overarching goal for Rubio and Cruz right now is to prevent Trump from winning the 1,237 bound delegates he needs to win the first ballot at the GOP convention in Cleveland this July. Super Tuesday shows that Trump is vulnerable and that Trump can be beaten. The question now is whether Rubio and Cruz have enough time to fatally weaken Trump before he runs away with the nomination. The clock is counting. We’ll likely have an answer in two weeks.